Herpesviridae

A family of DNA viruses known for causing diseases in animals and humans

Herpesviridae is a large family of DNA viruses that cause diseases in animals, including humans. Members of this family are known as herpesviruses. The family name is derived from the Greek word herpein ("to creep"), referring to the latent, recurring infections typical of these viruses.

Structure

Herpesviruses are characterized by their large, double-stranded DNA genome, which is enclosed within an icosahedral capsid. This capsid is surrounded by a tegument layer and a lipid envelope containing viral glycoproteins. The envelope is essential for the virus's ability to infect host cells.

Classification

The Herpesviridae family is divided into three subfamilies based on their biological properties:

• Alphaherpesvirinae: These viruses have a broad host range and are known for their rapid replication cycle. They establish latent infections primarily in sensory ganglia. Notable members include Herpes simplex virus (HSV) and Varicella zoster virus (VZV).

• Betaherpesvirinae: These viruses have a restricted host range and a slow replication cycle. They establish latency in monocytes and lymphocytes. Examples include Cytomegalovirus (CMV) and Human herpesvirus 6 (HHV-6).

• Gammaherpesvirinae: These viruses primarily infect lymphoid tissues and establish latency in B cells. Notable members include Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV).

Pathogenesis

Herpesviruses are known for their ability to establish lifelong latent infections in their hosts. During latency, the viral genome persists in host cells with minimal expression of viral genes. Reactivation can occur, leading to recurrent disease episodes. The mechanisms of latency and reactivation are complex and involve interactions between viral and host factors.

Diseases

Herpesviruses are responsible for a wide range of diseases in humans and animals. Some of the most common diseases include:

• Herpes simplex infections, causing oral and genital lesions.
• Chickenpox and shingles, caused by Varicella zoster virus.
• Infectious mononucleosis, caused by Epstein-Barr virus.
• Cytomegalovirus infection, which can be severe in immunocompromised individuals.
• Kaposi's sarcoma, associated with Kaposi's sarcoma-associated herpesvirus.

Transmission

Herpesviruses are typically transmitted through direct contact with infected bodily fluids or lesions. Some herpesviruses, such as CMV, can also be transmitted through organ transplantation or blood transfusion.

Prevention and Treatment

Preventive measures include avoiding contact with infected individuals and practicing safe hygiene. Vaccines are available for some herpesviruses, such as the varicella vaccine for chickenpox. Antiviral medications, such as acyclovir, can be used to manage symptoms and reduce the frequency of outbreaks.

Related pages

• Virus
• Virology
• Infectious disease